Do I have UD Pulleys?

[CobesSHO]

I bought the car used and I have noticed that the lights dim when idling. I've owned several Mustangs and installed UD Pulleys (including my current 05), so I know what effects they can have on your charging when idling, I just didn't notice it on the SHO until recently. I checked the alternator and at idle it charges the battery at a lower voltage and higher when the car is rev'd up (13.xx up to 14.xx), which appears to be OK. Does anyone know what the diameter of the different UD Pulleys are, Crank, Waterpump, Alternator, PS Pump? I'd like to measure them to see if someone in the past has installed the UD Pulleys, or if I have a problem with the charging system. Thanks!

 

[BlackonBlack89]

They are Aluminum so unless they are painted it should be pretty easy to notice.
That for the 3 peice setups. (Alt w/p, P/s pump). Idk about the 1-peice UDP crank pulley that are made today.

 

[38SHO]

i think they aftermarket crank pullies are all one piece, I.E. no rubber in them

if u have a small layer of rubber in your crank pulley then its probably stock

 

[PAracer]

Even the crank udp is aluminum. Every underdrive pully set that I am aware of is made from aluminum.

 

[SeanMc]

I don't know. Same symptoms could happen with a dieing battery, or alternator.

 

[38SHO]

I've seen UD crank pulley in steel for other cars.........

but x2 on dieing altenator..... same problem with my car then my alt really died

 

[Kens1992mtxSHO]

Chances are if you're not sure IF you've got UPDs you probably don't have them. I've seen a few UDP kits for the SHOs and all I've seen have been aluminum.

I would put my money on your alternator.

 

[LOUDSHO92]

Some ways to tell:

The pulleys look aluminum.

They have SHOShop stamped on them.

You have a solid crank pulley.

The PS pulley is solid.

 

[89SHOMAN666]

Even the crank udp is aluminum. Every underdrive pully set that I am aware of is made from aluminum.

Not correct. The alt pulley from the SHOShop 2 piece kit with was alt+crank the alt pulley was steel. The crank was a dampener with the inside piece made out of aluminum and the outside ring made from steel. Also the SHOShop 2 piece kit was manufactured by March so there is no SHOShop markings on it.

Hope this helps.

 

[hawkeye18]

I have a 3 piece UDP set on my ATX that has a PS pulley with large holes in it, a shiney WP pulley with holes in it, and a larger solid alt pulley.

 

[1993MTXSHO]

no really, everyone would be able to tell if they are UD if you could snap some pics of them. It is very obvious if they are UD or not